Collisional effects on trapped particle modes in tandem mirrors

Journal Article · Thu May 01 04:00:00 EDT 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865671· OSTI ID:5933719

Lane, B

The effects of collisions on trapped particle modes in tandem mirrors are analyzed. Two regimes are considered, a low collisionality regime ..omega..approx...omega../sup i//sub asterisk/>..nu../sub e/ and a high collisionality regime ..nu../sub i/<..omega..<..nu../sub e/. The magnetic geometry of the equilibrium is left arbitrary and a pitch angle scattering operator is used to model the effects of collisions. For ..omega..>..nu../sub e/ electron collisions are found to destabilize an otherwise stable negative energy wave. Because of a boundary layer phenomenon, the growth rate scales as (..nu../sub e/Vertical Bar..omega../sub asterisk/Vertical Bar)/sup 1//sup ///sup 2/. For ..nu../sub i/<..omega..<..nu../sub e/ two modes are obtained: (a) a flute mode whose stability is determined by the flux tube integral of the beta-weighted curvature drive, and (b) a dissipative trapped ion mode driven unstable by the difference in collisionality between electrons and ions. To first order in (..omega../..nu../sub e/), (..nu../sub i//..omega..), (..omega../sub d//..omega..), and k/sup 2//sub perpendicular/ rho/sup 2//sub i/ the stability and eigenfrequency of the flute mode is independent of ..nu../sub i/ while the dissipative trapped ion mode is damped by increasing ion collisionality.

• Research Organization: Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 5933719
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:5; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
BETA RATIO
BOUNDARY LAYERS
COLLISIONAL PLASMA
COLLISIONS
EIGENVALUES
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ENERGY LOSSES
FLUTE INSTABILITY
INSTABILITY
INSTABILITY GROWTH RATES
INTEGRALS
ION COLLISIONS
LAYERS
LOSSES
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
STABILITY
TANDEM MIRRORS
THERMONUCLEAR DEVICES
TRAPPED-PARTICLE INSTABILITY